Fig. 1. Electron microscopy. (  A and  B ) Lung tissue of healthy animals after 240 min of mechanical ventilation.  B is a magnification of a section of  A (  rectangle ). Mostly the membrane of type I pneumocyte stayed intact (  black arrowhead , B ); sporadically, signs of membrane disruption and partial detachment of endothelium occurred (  black arrow , B ). Animals that were allowed to recover for 2 days (group R) and unventilated healthy control animals (group C) showed no signs of membrane disruption and no detachment of endothelium (  C ). Animals ventilated with tidal volume of 16 ml/kg showed extensive damage with lungs appearing overinflated with loss of septal walls (  black arrowheads , D ) and injury of type I pneumocyte and endothelium (  inset , D ). Magnification:  A and  C : 5,000×;  B : 15,000×;  D : 3,000× (  inset 7,000×). E = erythrocyte; L = leukocyte; PI = type I pneumocyte; PII = type II pneumocyte.